docs: def set_bounds(self, lb, ub):
          """
          Change the lower and upper bounds of a variable.
          """
          if lb is not None and ub is not None and lb > ub:
              raise ValueError(
                  "The provided lower bound {} is larger than the provided upper bound {}".format(lb, ub)
              )
          self._lb = lb
          self._ub = ub
          if self.problem is not None:
              self.problem._pending_modifications.var_lb.append((self, lb))
              self.problem._pending_modifications.var_ub.append((self, ub))